The present invention relates to heat exchangers and more particularly to an improved construction for mounting the rotor assembly onto the shaft of a rotary regenerative heat exchanger.
In heat exchangers of the type under consideration, the rotor assembly is formed with a series of radial partitions circumferentially spaced about and carried by the shaft and including heat exchange elements disposed therebetween. The segmented rotor assembly is surrounded by a stationary housing having end plates formed with openings which direct the separate flow of a heating fluid and a fluid to be heated through the heat exchange elements. The separation of the two heat exchange fluids within the heat exchanger is accomplished through the use of sealing means which conform to the variations in clearance space between the housing and the rotor assembly. Such heat exchangers are normally constructed so that the axis of rotation for the rotor assembly extends along a line parallel to the flow path of the heat exchange fluids passing therethrough, with the heat exchange elements alternately absorbing heat from the heating fluid and yielding it to the fluid to be heated during each rotation of the rotor assembly. The fluid to be heated and the heating fluid are preferably in counter flow relation to one another with the inlet for the heating fluid and the outlet for the fluid to be heated being adjacent at one end of the heat exchanger, and the outlet for the heating fluid and the inlet for the fluid to be heated being adjacent the opposite end thereof. The rotor end facing the heating fluid inlet lies in a relatively high temperature zone and is commonly referred to as the "hot end" whereas the end facing the heating fluid outlet lies in a relatively low temperature zone and is commonly referred to as the "cold end". While the length of the flow path through the rotor assembly may be comparatively small, the temperature gradients occurring between the "hot" and "cold ends" are appreciable and lead to non-uniform thermal expansion and unequal stresses which often result in breakage of the rotor connection to the shaft.